Linear because there is a constant change (+3)
X= -5/8-5/8√33 or x= -5/8+5/8 √<span>33</span>
It's D, because the mean doesn't matter as much if it's only taken in a small variability. The mean was selected from 25 random pages in the book, that is why it is right.

so we have a 33, namely two real solutions for that quadratic.
usually that number goes into a √, if you have covered the quadratic formula, you'd see it there, namely that'd be equivalent to √(33), now 33 is a prime number, and √(33) is yields an irrational value, specifically because a prime number is indivisible other than by itself or 1.
so 33 can only afford us two real irrational roots.